In the Company of Volcanoes

I just returned from two, very warm, weeks in Italy. The group wanted to go somewhere with volcanoes and good food, so Italy was a natural choice. While Italian geology is fascinating in its own right, that will have to be saved for a different post. Today's post is a bit of urban geology.  I found that I spent most of my time in Rome looking at the building stone, and took mostly pictures of rocks and stone. The Romans collected the most beautiful stone from their empire and then used to make buildings and show off their wealth. These stones were then scavenged from Roman sites to build the next round of impressive buildings by the Catholic Church. So when you tour buildings in Rome it includes a geologic tour of the whole Mediterranean. While most visitors expect Rome to made of endless white marble there are a range of stone types from around the far reaches of the Roman Empire. One of the classic stone types used to impress visitors is this deep red porphyry from Egypt. Po